2Haipeng Pan,Wei Xing. Design of a new intelligent PID con- trol system of greenhouse temperature [J].Proceedings of the 7thWorld Congress on Intelligent Control and Automation, Chongqing,China, 2001 (6) : 25 -27.
3Li F,Bai X H,Li J W.Study on the greenhouse control system based on PID eontrol[J].Journal of AgriculturalMeehanization Research,2005(1):83-84.
4Sigrimis N A,Arvanitis K G,Pasgianos G D.Synergism of high and low level systems forthe efficient management of green- houses[J]. Computers and Electronics in Agriculture,2000,29: 21-39.
5Astrom K,Hagglund T.PID Controllers:Theory,Design and Tu- ning[M]. ISA Publications,Researeh Triangle Park, NC. 1988.